Astrovirus

Under the electron microscope, astroviruses appear as small, round viruses that have surface projections resembling a five- or six-pointed star.of positive-sense single stranded RNA.hence the name Astroviridae. Astroviruses are heat resistant for short periods above 56°C and survive for long periods below -20°C.

Characteristics
Shape and Size
20-39nm. star-shaped
Genome Information
Astrovirus is a positive-strand viruses ( GI:-209902360) has a 6171 bp single stranded linear RNA.The genome structure consists of 3 genes and 3 proteins.The GC content of Astrovirus about 40.9%.
Food Source
Meat and Meat Products
Pathological Factor
Viral particles have been visualized by EM in intestinal epithelial cells and in epithelial cells located in the lower part of the villi, suggesting that the intestine is the site of replication.  Astrovirus pathogenesis has been studied in lambs and calves, using ovine and bovine astrovirus isolates, respectively. Infection of lambs induces a mild transient diarrhea that occurs 2 days after infection and lasts approximately 2 days. Infection of calves with at least one strain of bovine astrovirus did not induce diarrheal illness, although the infection was associated with sloughing of infected villus cells.
Disease
Acute diarrhea
Symptoms
syptoms are watery diarrhae, fever, anorexia and abdominal pain.
Affected Body Organs
gastro intestinal organs

Classification
Group Group-IV-((+)ssRNA)
Family Astroviridae
Genus Avastrovirus
Species Avian-nephritis virus